The first evidence of a Denisova man in the tropics

Une dent d’enfant vieille d’au moins 130,000 ans découverte dans une grotte au Laos témoigne de la présence des hommes de Denisova dans le climat tropical d’Asie du Sud-Est, levant une partie du le voile de pares ère è , according to a study.

Very little is known about the Denisovan, the ancient human cousin of Neanderthals, who was first identified in 2010 in a cave in Siberia. From a simple piece of phalanx, paleontologists have been able to sequence an entire genome. Then, in 2019, they found the large-toothed mandible on the Tibetan plateau, proving that the species also lived in this part of China.

see also – ‘Extraordinary discovery’: Neanderthal fossils found in a cave in Italy

Hybridization with Homo sapiens

Apart from these rare fossils, the Denisovans left no trace of his passage … except for genes. Since before the disappearance, this so-called ancient species interbred with Homo sapiens, inheriting part of its DNA for today’s inhabitants of Southeast Asia and Oceania: the Negrito possesses of The Philippines and Papua of New Guinea and the indigenous people of Australia make up a large proportion of the Denisovan genome – up to 5%.

Geneticists have concluded thatIt was the ancestors of these modern peoples cross With Denisovans in Southeast Asia‘, explains to AFP paleontologist Clement Zanulli, co-author of the study, which was published Tuesday in Nature Communications.tangible evidenceFrom their presence in this part of the Asian continent, far from the cold mountains of Siberia or Tibet, adds the researcher of the National Center for Scientific Research. Until a team of scientists set out to excavate the Cobra Cave in northeastern Laos.

Morphology “usually human”

The cavity, located on a massif, was discovered in 2018 by speleologists near the site of Tam Pa Ling, which is known to have already delivered the remains of ancient humans. The sediments preserved in the cave walls contained bony fragments of animals, as well as a molar. Old age spot morphologyhuman habitClément Zanoli says. The study said it must have belonged to a child between the ages of 3 and 8 because he was still developing in his jaw.

But from what era, what species? The tooth was too old for carbon-14 dating, and its DNA is poorly preserved due to the hot and humid climate, confirms paleoanthropologist Fabrice Demeter, co-author. So the researchers circumvented the obstacle by dating the sediments containing the teeth and animal remains, then the upper layer, to get a range of 160,000 to 130,000 years.

little molar girl

Then they studied the interior of the tooth – which was temporarily exported to Denmark – using various methods such as X-ray microscopy and paleoproteomics (protein analysis). “Proteins allowed us to identify the gender, the female, and confirm her membership in the human raceExplains Fabrice Demeter, a researcher at the University of Copenhagen affiliated with the National Museum of Natural History in Paris.

Surprisingly, the internal structure of the tooth turned out to be close to the molars of the Denisova specimen from Tibet. “I was really expecting Homo erectus!‘,” states the paleontologist. But undoubtedly, the molar was easy to distinguish from this ancient species, as well as other extinct groups endemic to the Philippines and Indonesia, Homo floresiensis and Homo luzonensis.

“Ingenuity” that rejects the influence of Neanderthals

And of course the modern man. The only problem: It had characteristics in common with Neanderthals, a genetically close relative to Denisovans – the two species had diverged about 350,000 years ago.

But we headed toward Denisova, because we found no trace of Neanderthals passing through the East either.‘, identifies Clément Zanolli. The study concludes that Denisovans have already occupied this part of Asia, a sign of adaptation to a wide range of environments, from cold altitudes to tropical climates. A “cleverness“that their Neanderthal cousins ​​did not seem to have, any more”specialized» In the cold regions of the West, Fabrice Demeter details.

It was the tropics that the later Denisovans may have encountered and crossed with modern local human groups in the Pleistocene era, who passed on their genetic heritage to the present-day population of Southeast Asia.


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